Admin homepage can say "page isn’t redirecting properly"

[klor]

My browser says "The page isn’t redirecting properly" in this scenario:

1. Log into the editing interface - here: http://www.example.com/processwire/
   User is now redirected to: http://www.example.com/processwire/page/?login=1

2. Delete your cookies (or log out on another tab in your browser)
   (You are here: http://www.example.com/processwire/page/?login=1)

3. Refresh the page or type enter in the web address field
   (You are here: http://www.example.com/processwire/page/?login=1)

4. Result:
   Firefox 55 now says "The page isn’t redirecting properly".
   (You are here: http://www.example.com/processwire/page/?login=1)

ProcessWire 3.0.62

[mikerockett]

Please open your issue here instead: https://github.com/processwire/processwire-issues/issues (per #2051)